girl gets kidnapped and gets helped by daughter of kidnapper

basically this girl gets left in her mom’s van and it gets stolen from a gas station. the kidnappers daughter gives her food and help. she gets reunited with her family but years later meets the girl at a summer camp. they wrote on rocks (camp tradition) and put them in a wall.

i read this prolly in middle school (2014-2017) and i think the title only had 1 word (i think?). this book has stuck with me ever since and it haunts me that i have no idea what it’s called.